Probing the temperature of supported platinum nanoparticles under microwave irradiation by in situ and operando XAFS.

ABSTRACT: Microwave irradiation can cause high local temperatures at supported metal nanoparticles, which can enhance reaction rates. Here we discuss the temperature of platinum nanoparticles on γ-Al₂O₃ and SiO₂ supports under microwave irradiation using the Debye-Waller factor obtained from in situ extended X-ray absorption fine structure (EXAFS) measurements. Microwave irradiation exhibits considerably smaller Deby-Waller factors than conventional heating, indicating the high local temperature at the nanoparticles. The difference in the average temperatures between the platinum nanoparticles and the bulk under microwaves reaches 26 K and 132 K for Pt/Al₂O₃ and Pt/SiO₂, respectively. As a result, Pt/SiO₂ exhibits considerably more reaction acceleration for the catalytic dehydrogenation of 2-propanol under microwave irradiation than Pt/Al₂O₃. We also find microwaves enhance the reduction of PtO_x nanoparticles by using operando X-ray absorption near edge structure (XANES) spectroscopy. The present results indicate that significant local heating of platinum nanoparticles by microwaves is effective for the acceleration of catalytic reactions.

SUBMITTER: Ano T 

PROVIDER: S-EPMC9814256 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature